Inhibition Of 5alpha-reductase By A Peptide-conjugated Compound Of Finasteride

Prostate diseases on the health hazards of the elderly men is becoming more and more harmful as the extent of aging population is increasing clear. Benign prostatic hyperplasia (BPH) is the most important class of prostate disease. It will lead to emergence of urgency, urinary frequency and dysuria and other symptoms, and if not treated in time it will be subject to prostate cancer. Most of existing drugs of BPH have greater side effects and cost more. So a safe, effective and relatively inexpensive treatment for BPH is in urgent need in BPH clinical research. The results have shown that in vivo, 5αreductase is an NADPH-dependent enzyme that catalysis the reduction of testosterone (T) to the more biologically active dihydrotestosterone (DHT), and the accumulation of DHT in prostate tissue is main reason for BPH. The inhibition of 5αreductase activity can reduce the DHT levels in vivo, so as to achieve the effect of inhibition of BPH. Thus 5αreductase inhibitors can be used as an effective drug for the treatment of BPH. Finasteride is a selecting 5αreductase inhibitor which has been allowed to list on the market, and it has good inhibitory effect of activity of 5αreductase. Pidotimod is a short peptide and it can contribute to the regulation of immunization in order to perform a role of anti-viral. By the enlightenment of the steroidal reaction with glycoside and peptide, we get a new compound which is formulated by finasteride and pidotimod. We are ready to conduct a study on the new compound in the inhibitory of activity of 5αreductase, to observe whether the new compound has the nature of the two - both to strengthen the pharmacological role of finasteride and enhancing the capacity of immune regulation at the same time, reducing the toxic side effects. So as to exploring a new way to develop new drugs for the treatment of BPH.The first section of study is in vitro experiments:Strategy: Set up a system for detection of 5αreductase enzyme activity, using spectrophotometer at a wavelength of 340nm in detection of the change of NADPH content in which 5αreductase catalytic reaction of T into DHT, thereby we can indirectly detect the change of 5αreductase activity. Further, according to the relationship between enzyme reaction rate, substrate concentration and inhibitor concentration, we use Lineweaver-Burk plot and Dixon plot to carry out a comparative analysis so as to determine the inhibition of the inhibiton nature, constant and IC50 of the drug.Results: The type of inhibition of Finasteride against 5α-reductase activity is predominantly competitive reversible inhibition, the inhibition constant Ki = 23.93±0.33nM, IC50 = 147.49± 2.84nM, The type of inhibition of biological peptide-based compound of Finasteride is as well as Finasteride, the inhibition constant Ki = 34.83±0.24nM, IC50 = 87.98±1.76nM. The inhibitory effect of 5α-reductase activity of biological peptide-based compound of Finasteride in vitro is better than Finasteride.The second section of study is in vivo experiments:Strategy: Establish a castrated rat model of benign prostatic hyperplasia induced by testosterone propionate.In this model, give subcutaneous administration to rats in two weeks, after that detect prostate index and the weight of prostate. Then we use HE staining in detection of castrated rat prostate tissue and analyze structural changes.Results: BPH animal model has been successful. Results show that the weight of prostate and prostate index of the model group rat have a significant increasement(P <0.05)compared with the normal group. Judging from the administration result, the weight of prostate and prostate index in different doses of biological peptide-based compound of Finasteride treatment group rat, compared with the BPH model, has dropped significantly (P <0.01). Judging from the results of observation of the prostate tissue, compared with the normal group, biological peptide-based compound of Finasteride treatment group rat have more regular arrangement of the prostate gland, less stratified glandular epithelial cells, and the convex situation of glands papillary epithelial processes occurs rarely. The overall symptoms of benign prostatic hyperplasia appears to be significantly improved.In conclusion, compared to Finasteride, biological peptide-based compound of Finasteride has more effective inhibitory of 5α-reductase activity and more visible effect in the treatment of benign prostatic hyperplasia in castrated rats,suggesting that drug toxicity and safety may be more advantageous. This proves that this new ideas in the research of peptide-based compound of steroid in the treatment of BPH is feasible. On the basis of the research, we can make in-depth study in the other aspects of peptide-based compound of steroid and develop more new drugs as soon as possible.